Fix playback + download of default torrents

There was a terrible bug introduced in 0809e20a6e -- clicking play on any of the default torrents in a fresh install of the app would fail and result in a 'path missing' error.

This fixes the bug, and also adds a migration step to clean up resulting broken config files

src/renderer/controllers/torrent-list-controller.js

@@ -84,21 +84,30 @@ module.exports = class TorrentListController {
     var s = TorrentSummary.getByKey(this.state, torrentKey)
     if (!s) throw new Error('Missing key: ' + torrentKey)
 
-    // Use Downloads folder by default
-    if (!s.path) s.path = this.state.saved.prefs.downloadPath
+    // New torrent: give it a path
+    if (!s.path) {
+      // Use Downloads folder by default
+      s.path = this.state.saved.prefs.downloadPath
+      return start()
+    }
 
+    // Existing torrent: check that the path is still there
     fs.stat(TorrentSummary.getFileOrFolder(s), function (err) {
       if (err) {
         s.error = 'path-missing'
         return
       }
+      start()
+    })
+
+    function start () {
       ipcRenderer.send('wt-start-torrenting',
         s.torrentKey,
         TorrentSummary.getTorrentID(s),
         s.path,
         s.fileModtimes,
         s.selections)
-    })
+    }
   }
 
   // TODO: use torrentKey, not infoHash

src/renderer/lib/migrations.js

@@ -4,8 +4,10 @@ module.exports = {
   run
 }
 
-var semver = require('semver')
-var config = require('../../config')
+const semver = require('semver')
+const config = require('../../config')
+const TorrentSummary = require('./torrent-summary')
+const fs = require('fs')
 
 // Change `state.saved` (which will be saved back to config.json on exit) as
 // needed, for example to deal with config.json format changes across versions
@@ -110,4 +112,26 @@ function migrate_0_12_0 (saved) {
     saved.prefs.openExternalPlayer = saved.prefs.playInVlc
   }
   delete saved.prefs.playInVlc
+
+  // Undo a terrible bug where clicking Play on a default torrent on a fresh
+  // install results in a "path missing" error
+  // See https://github.com/feross/webtorrent-desktop/pull/806
+  var defaultTorrentFiles = [
+    '6a9759bffd5c0af65319979fb7832189f4f3c35d.torrent',
+    '88594aaacbde40ef3e2510c47374ec0aa396c08e.torrent',
+    '6a02592d2bbc069628cd5ed8a54f88ee06ac0ba5.torrent',
+    '02767050e0be2fd4db9a2ad6c12416ac806ed6ed.torrent',
+    '3ba219a8634bf7bae3d848192b2da75ae995589d.torrent'
+  ]
+  saved.torrents.forEach(function (torrentSummary) {
+    if (!defaultTorrentFiles.includes(torrentSummary.torrentFileName)) return
+    var fileOrFolder = TorrentSummary.getFileOrFolder(torrentSummary)
+    if (!fileOrFolder) return
+    try {
+      fs.statSync(fileOrFolder)
+    } catch (e) {
+      // Default torrent with "missing path" error. Clear path.
+      delete torrentSummary.path
+    }
+  })
 }